1. Technical Field
The present invention relates to a light emitting device, a super luminescent diode, and a projector.
2. Related Art
A super luminescent diode (hereinafter, also referred to as “SLD”) is a semiconductor light emitting device that has a broadband spectrum shape and thus exhibits incoherence like a typical light emitting diode. A single SLD can provide output of several hundreds of milliwatts like a semiconductor laser.
An SLD is sometimes used as a light source of a projector, for example. It is necessary to use a light source with high light output and small etendue for realization of a compact and high-brightness projector. For this purpose, it is desirable that the light emitted from an optical waveguide travel in the same direction. For example, JP-A-2011-155103 discloses a light emitting device including an optical waveguide in which the light traveling direction changes in a reflection part (reflection surface) of an active layer, and the light emitting device may allow the light emitted from two light emitting parts to travel in the same direction.
However, in the light emitting device, it is difficult to form the reflection part (reflection surface) on a flat surface at an atomic level, and minute irregularities may be formed in the reflection part. Accordingly, heat may be generated due to non-radiative recombination in the reflection part and a cladding layer near the reflection part, optical absorption in the reflection part may increase due to the heat generation, and COD (Catastrophic Optical Damage) destruction may occur in the reflection part.